The UEC68LSE and UEC52LSE engines are developed mainly as the main engines of the cape size and panamax bulk carriers respectively.
At present four sets of 6UEC52LSE engines are on order with KOBE DIESEL CO., Ltd. which is another licensee in Japan and will be in test running in the beginning of 2001.
Details of these new UEC-LSE engines are described in chapter 3.
2. RESULTS OF RELIABILITY VERIFICATION TEST FOR THE UEC37LS II
The first UEC37LS II is a 6-cylinder engine and was manufactured by AKASAKA DIESELS Ltd. Fig.3 shows the outside view of this engine and Table 1 lists the main particulars. This engine with the piston diameter of 370 mm, the stroke of 1290 mm is in smaller class among UEC-LS II series. BMEP of 18.0 bar is selected, approx. 3.5% higher than existing UEC-LS II engines and the engine has output of 772.5 kW/cylinder. The official shop test was successfully completed on May 23 after reliability verification test for approx. 2 weeks. The following paragraph describes the features on construction of the engine and the result of reliability verification test.
2.1 Main features of construction
Fig.4 shows the main construction features of UEC37LS II engine. Both the column integrated with camshaft casing and the bed plate are made of monoblock casting. The cylinder jacket is extended and integrates cylinder liner support and scavenging trunk. And the jacket type cooling is applied to cylinder liner and cover.
The arrangement of the exhaust gas manifold is optimized in order to reduce engine height and improve the vibration characteristic.
Like the above, the construction is simplified, and the maintenance and the reliability are improved.
2.2 Result of Engine performance test
In order to optimize the engine performance, various tests including turbocharger-matching were carried out on the combustion system fuel injection system and scavenging and exhaust systems. Fig.5 is the engine performance curve with the condition that engine was optimized. The each engine parameter of scavenging air pressure, maximum cylinder pressure, exhaust gas temperature before and after turbocharger and specific fuel oil consumption rate, sufficient results, which correspond with the designed figures were obtained as the results.
2.3 Temperature of the combustion chamber
Fig.6 shows the measured temperature of the combustion chamber at 100% load. The maximum piston crown temperatures on combustion side and on cooling side are 351℃ and 150℃ respectively which were equivalent to or even lower than those measured in the existing UEC-LS II series, thus, the reliability of the piston crown was verified. It was confirmed that the speed type cooling method of the piston crown, which is the same as that applied in the existing UEC-LS II series, is effective for high output engine.
The measured cylinder liner wall temperature is 221℃ at the top ring TDC position which is optimized against both sides of low temperature corrosion and high temperature that causes lubrication oil film breakage. The cylinder liner running condition after the official shop test is shown in a photograph of Fig.7 and very good condition was confirmed.
